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United States Patent |
6,161,290
|
Takamasa
|
December 19, 2000
|
Utility knife
Abstract
A utility knife having a holder body for supporting a blade slidably
between a protruded position and a returned position, the utility knife
comprising a spring means to be operated against a slider supporting the
blade, a slider for manually moving said blade to a protruded position, a
lock means for locking the slide movement of said slider at said protruded
position resisting against the spring force of the spring means, and a
means for releasing the lock of said lock means, wherein upon use, the
blade temporarily fixed to the slider will be protruded from the holder by
manually sliding said slider, and the blade could be locked at the end
position of the slide. When storing the blade, the lock could be released
by pressing on the lock release button, which allows the slider to be
pulled back by the spring, and along with this movement, the blade could
be stored automatically inside the holder body.
Inventors:
|
Takamasa; Mitsuhiro (Kyoto, JP)
|
Assignee:
|
Kyoto Measuring Instruments Corp. (Kyoto, JP)
|
Appl. No.:
|
998558 |
Filed:
|
December 29, 1997 |
Foreign Application Priority Data
Current U.S. Class: |
30/162; 30/320; 30/335 |
Intern'l Class: |
B26B 001/00 |
Field of Search: |
30/160,161,162,320,335,294
|
References Cited
U.S. Patent Documents
3863339 | Feb., 1975 | Reaney et al. | 30/162.
|
4028758 | Jun., 1977 | O'Conner | 30/162.
|
4621425 | Nov., 1986 | Stoutenberg | 30/162.
|
4835865 | Jun., 1989 | Knoop | 30/162.
|
4910821 | Mar., 1990 | Kieferle | 7/158.
|
5012581 | May., 1991 | Fletcher et al. | 30/162.
|
5203085 | Apr., 1993 | Berns | 30/162.
|
5299355 | Apr., 1994 | Boda et al.
| |
5426855 | Jun., 1995 | Keklak et al. | 30/162.
|
5495670 | Mar., 1996 | Quinn | 30/162.
|
5581890 | Dec., 1996 | Schmidt | 30/162.
|
5617635 | Apr., 1997 | Berns | 30/162.
|
5813121 | Sep., 1998 | Gringer | 30/162.
|
5870828 | Feb., 1999 | Polites | 30/162.
|
Primary Examiner: Rachuba; M.
Attorney, Agent or Firm: Jordan and Hamburg LLP
Claims
What is claimed is:
1. A utility knife having a holder body for supporting a blade slidably
between a protruded position extending out of the holder body and a
returned position retracted within the holder body at a position where a
cutting edge of the blade is not exposed, the utility knife comprising:
a slider means for sliding the blade in a protruding direction to the
protruded position;
a means for biasing the blade in a returning direction to return the blade
from the protruded position to the returned position;
a lock mechanism for locking slide movement of the blade at said protruded
position to resist against the means for biasing the blade in the
returning direction, said lock mechanism for locking including:
a leaf-spring mounted on the slider means and having an end portion biased
toward an inner wall of said holder body; and
a step portion formed on said inner wall of said holder body for engaging
said end portion of said leaf-spring when said end portion passes over
said step portion during sliding of the blade in the protruding direction
such that movement of said leaf-spring and said slider means in the
returning direction is prevented; and
a means for releasing said lock mechanism to permit return of the blade to
the returned position by action of said means for biasing, said means for
releasing including a release button movably disposed in said holder body
permitting displacement by a user to a position engaging and displacing
said leaf-spring to remove said end portion of said leaf-spring from
engagement with said step portion.
2. The utility knife of claim 1, wherein said release button is movably
disposed such that movement in directions other than substantially
orthogonal to said protruding direction and said returning direction is
restricted.
3. The utility knife of claim 1 wherein the step portion has a step surface
facing in the protruding direction which is engaged by said end portion of
said leaf-spring to lock the slider means in position preventing said
means for biasing from returning said slider means and said blade to the
returned position.
4. The utility knife of claim 1, wherein said means for sliding the blade
in said protruding direction is a slider on which said blade is supported.
5. The utility knife of claim 4, wherein said holder body has a groove slot
extending in a sliding direction of said slider and said slider has a
protrusion protruded outwardly through said groove slot for actuation of
said slider by a finger of a user to extend said blade to said protruded
position from said returned position.
6. The utility knife of claim 1, wherein said means for releasing said lock
mechanism includes:
an elastic strip member connecting said release button to said inner wall
in a biased state permitting said release button to engage said
leaf-spring; and
an aperture in said inner wall permitting user deflection of said release
button into said leaf-spring member to displace said end portion of said
leaf-spring member from said engagement with said step portion and thereby
permit said means for biasing the blade to return said blade to the
returned position.
7. The utility knife of claim 6 wherein said release button has a head
surface upon which a user presses to release said lock mechanism and said
head surface is normally biased at a position even with an outside body
surface of said holder body.
8. A utility knife having a holder body for supporting a blade slidably
between a protruded position extending out of the holder body and a
returned position retracted within the holder body at a position where a
cutting edge of the blade is not exposed, the utility knife comprising:
a slider for supporting said blade and for manually moving said blade to
said protruded position;
a spring means for biasing said slider in a returning direction to return
the blade from the protruded position to the returned position;
a lock mechanism for locking slide movement of said slider at said
protruded position to resist against spring force of the spring means,
said lock mechanism including:
a leaf-spring mounted on the slider and having an end portion biased toward
an inner wall of said holder body; and
a step portion formed on said inner wall of said holder body for engaging
said end portion of said leaf-spring when said end portion passes over
said step portion during sliding of the blade in the protruding direction
such that movement of said leaf-spring and said slider in the returning
direction is prevented; and
a means for releasing locking action of said lock mechanism on said slide
movement of said slider, said means for releasing including a release
button movably disposed in said holder body permitting displacement by a
user to a position engaging and displacing said leaf-spring to remove said
end portion of said leaf-spring from engagement with said step portion.
9. The utility knife of claim 8, wherein said release button is movably
disposed such that movement in directions other than substantially
orthogonal to said protruding direction and said returning direction is
restricted.
10. The utility knife of claim 8 wherein the step portion has a step
surface facing in the protruding direction which is engaged by said end
portion of said leaf-spring to lock the slider in position preventing said
spring means from returning said slider and said blade to the returned
position.
11. The utility knife of claim 8, wherein said blade is supported on said
slider.
12. The utility knife of claim 11, wherein said holder body has a groove
slot extending in a sliding direction of said slider and said slider has a
protrusion protruded outwardly through said groove slot for actuation of
said slider by a finger of a user to extend said blade to said protruded
position from said returned position.
13. The utility knife of claim 8, wherein said means for releasing said
lock mechanism includes:
an elastic strip member connecting said release button to said inner wall
in a biased state permitting said release button to engage said
leaf-spring; and
an aperture in said inner wall permitting user deflection of said release
button into said leaf-spring member to displace said end portion of said
leaf-spring member from said engagement with said step portion and thereby
permit said spring means to return said blade to the returned position.
14. The utility knife of claim 13 wherein said release button has a head
surface upon which a user presses to release said lock mechanism and said
head surface is normally biased at a position even with an outside body
surface of said holder body.
15. A utility knife having a holder body for supporting a blade slidably
between a protruded position extending out of the holder body and a
returned position retracted within the holder body at a position where a
cutting edge of the blade is not exposed, the utility knife comprising:
a slide means for sliding the blade in a protruding direction to the
protruded position;
a means for biasing the blade in a returning direction to return the blade
from the protruded position to the returned position; and
a lock mechanism for locking slide movement of the blade at said protruded
position to resist against the means for biasing the blade in the
returning direction, said lock mechanism for locking including:
a leaf-spring mounted on the slider means and having an end portion biased
toward an inner wall of said holder body; and
a step portion formed on said inner wall of said holder body for engaging
said end portion of said leaf-spring when said end portion passes over
said step portion during sliding of the blade in the protruding direction
such that movement of said leaf-spring and said slider means in the
returning direction is prevented; and
a means for releasing said lock mechanism to permit return of the blade to
the returned position by action of said means for biasing, said means for
releasing being a means for displacing said leaf-spring to remove said end
portion of said leaf-spring from engagement with said step portion.
16. The utility knife of claim 15, wherein said means for displacing said
leaf-spring is a lock release button mechanism including:
a button portion;
an elastic strip member connecting said button portion to said inner wall
in a biased state permitting said button portion to engage said
leaf-spring; and
an aperture in said inner wall permitting user deflection of said button
portion into said leaf-spring member to displace said end portion of said
leaf-spring member from said engagement with said step portion and thereby
permit said means for biasing the blade to return said blade to the
returned position.
17. The utility knife of claim 15, wherein said slide means for sliding the
blade in said protruding direction is a slider on which said blade is
supported.
18. The utility knife of claim 17, wherein said holder body has a groove
slot extending in a sliding direction of said slider and said slider has a
protrusion protruded outwardly through said groove slot for actuation of
said slider by a finger of a user to extend said blade to said protruded
position from said returned position.
19. The utility knife of claim 1 or claim 8 wherein said release button has
a head surface upon which a user presses to release said lock mechanism
and said head surface is normally disposed at a position even with an
outside body surface of said holder body.
Description
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a utility knife, and more particularly, to
a utility knife with a structure for enabling the blade of the utility
knife to be fixed at the state where it is protruded from the holder body
of the utility knife, and also to be stored inside the holder body by an
easy operation.
BACKGROUND OF THE INVENTION
From the past, utility knifes with fixed protruded blades were popular, but
recently, improved utility knives with a slide structure where a slider
with a blade fixed thereto could be manually slided in back and forth
directions by hand, and further could be stored inside the holder body are
well known.
In addition to that, products with consideration for safety characteristics
exist wherein the slider holding the blade could be slided manually, but
when after use, the slider, and thereby the blade, is pulled back inside
the holder body.
This type of utility knife is disclosed for example in Japanese Laid-Open
Utility Model Publication No. 56-111970 which is a knife where the blade
is protruded from the holder body by holding the body by the hand and
sliding the slider body against the elastic body by a thumb, and when the
cutting operation is finished, the user releases the thumb and the slider
is pulled back by the elastic body, storing the blade back inside the
holder body. An improved example of such type of utility knife is
disclosed in Japanese Laid-Open Patent Publication No. 6-315577 wherein
the slider body comprises a main slider and a sub slider, the main slider
adjusts briefly the amount of blade to be protruded from the holder body,
and the sub slider adjusts in detail said amount of blade protrusion,
enabling an exact adjustment of the protrusion of the blade.
However, these products were not very convenient in that the blades could
not be fixed in a protruded state from the holder of the knife, and the
user had to hold the slider during the whole time of use to keep the
protruded state of the blade.
With consideration to the above problem, there is an invention disclosed in
Japanese Laid-Open Patent Publication No. 5-212161 wherein the blade could
be stopped at the protruded state from the knife body, and when the knife
is not used, the blade of the knife could be returned to the protective
position by use of a spring.
This invention, however, has safety problems in that the matching teeth
mounted on the extending portion of the knife holding body for
exchangeably holding the knife and the concave matching portion of the
stopper nail supported rotatably on the gripping body of the knife is held
together in a stop position by the spring force enforcing the knife
holding body in the returning direction, and this stop is released by the
centrifugal force operated to the stopper nails. Therefore, the operation
of the knife was not stable, and a swinging movement of the knife itself
to occur centrifugal force was dangerous.
SUMMARY OF THE INVENTION
The present invention aims at solving the above-mentioned problems wherein
the first object of the invention is to provide a utility knife whose
blade could be fixed at a using state where the blade is protruded from
the knife holder body.
The second object of the present invention is to provide a utility knife
whose blade fixed at a using state with the blade protruded from the knife
holder body could be stored inside the knife holder body automatically by
a simple and certain operation at the time of storage.
A utility knife of the present invention having a holder body for
supporting a blade slidably between a protruded position and a returned
position, the utility knife comprises:
a means for sliding the blade toward a protruding direction;
a means for forcing the blade toward a returning direction; and
a means for locking the slide movement of the blade at said protruded
position resisting against the means for forcing the blade toward the
returning direction.
A utility knife of the present invention having a holder body for
supporting a blade slidably between a protruded position and a returned
position, comprises:
a means for sliding the blade toward a protruding direction;
a means for forcing the blade toward a returning direction;
a means for locking the slide movement of the blade at said protruded
position resisting against the means for forcing the blade toward the
returning direction; and
a means for releasing said lock.
In the utility knife of the present invention, said means for sliding the
blade toward a protruding direction is a slider on which said blade is
supported.
In the utility knife of the present invention, said slider comprises a
protrusion protruded outwardly through a groove formed on said holder body
for placing a finger of a user.
In the utility knife of the present invention, said means for forcing the
blade toward a returning direction is a spring means connected to said
slider.
A utility knife of the present invention having a holder body for
supporting a blade slidably between a protruded position and a returned
position, comprises:
a slider for supporting said blade and for manually moving said blade to a
protruded position;
a spring means for forcing said slider toward a returning direction; and
a lock means for locking the slide movement of said slider at said
protruded position resisting against the spring force of the spring means.
A utility knife of the present invention having a holder body for
supporting a blade slidably between a protruded position and a returned
position, comprises:
a slider for supporting said blade and for manually moving said blade to a
protruded position;
a spring means for forcing said slider toward a returning direction;
a lock means for locking the slide movement of said slider at said
protruded position resisting against the spring force of the spring means;
and
a means for releasing the lock of said lock means.
In the utility knife of the present invention, said lock means for locking
the slide movement is a stopper in the shape of a leaf-spring mounted on
the slider, and a step portion formed on a sliding wall of said slider of
the utility knife.
In the utility knife of the present invention, said means for releasing the
lock of said lock means is a means for releasing a fit connection of a
stopper in the shape of a leaf-spring mounted on the slider and a step
portion formed on a sliding wall of said slider of the utility knife.
In the utility knife of the present invention, said means for releasing a
fit connection is a lock release button comprising a head portion and an
elastic strip member extending from said head portion and being fixed to
an inner wall of said utility knife.
By the above structure, the present invention solved the inconvenience of
the prior utility knife wherein the user must hold the slider with the
finger to keep the blade protruding from the knife holder body, and the
present invention enabled to store the blade inside the knife holder
automatically with the use of a spring simply by pressing on the lock
release button. Therefore, a safe and useful utility knife could be
provided.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing,
FIG. 1 is a plain view of the utility knife holder body of the present
invention;
FIG. 2 is a front view of the utility knife holder of the present
invention;
FIG. 3 is a bottom view of the utility knife holder body of the present
invention;
FIG. 4 is a cross-sectional view taken along line A-A' of FIG. 2 showing
the state where the blade is stored inside the holder body;
FIG. 5 is a cross-sectional view as in FIG. 4 showing the state where the
blade is protruded from the holder body;
FIG. 6 is a cross-sectional view taken along line B-B' of FIG. 1 showing
the state where the blade is stored inside the holder body;
FIG. 7 is a cross-sectional view as in FIG. 6 showing the state where the
blade is protruded from the holder body;
FIG. 8 is an enlarged view of the main portion of FIG. 7 showing the
structure for fixing the blade at the protruded state; and
FIG. 9 is an enlarged view as in FIG. 8 showing the structure for releasing
the fixed state of the blade.
PREFERRED EMBODIMENT OF THE INVENTION
FIG. 4 is a cross-sectional view of a utility knife of the present
invention, wherein upon use, a blade 2 temporarily fixed to a slider 3
could be protruded from a holder by sliding said slider 3 manually,
enabling the blade to be fixed by locking the slider at the end portion.
Further, when storing said blade 2, a lock release button 4 (refer to FIG.
9) could be pressed to release the lock portion of the holder, thereby
pulling the slider back by a spring, and storing the blade inside a holder
body 1 automatically.
As is shown in FIG. 6, a portion of the slider is formed as a leaf spring
member 33 which works as a stopper. When the slider 3 is moved toward the
forward direction of the knife holder body 1 and the front end portion of
said leaf spring member passes a step portion of the holder body 1, that
is, when the blade reaches a protruding position at the end of the slide,
and when the finger is released from the slider, the slider will be pulled
back by the spring 5, but the end portion of the leaf spring member 3 is
caught at the step portion, thereby providing a lock as shown in FIG. 8.
In order to release the lock by pressing the lock release button 4 as shown
in FIG. 9, the end portion with the leaf spring member of the slider 3
will be pressed and released from the step portion 14 of the holder.
The slider 3 and the holder body 1 is connected by a spring 5, and when the
lock is released, the slider 3 will be pulled back inside the knife holder
body 1 by the spring 5, and the blade 2 temporarily fixed to the slider
will be stored inside the holder body 1.
Holder Body
The holder body 1 of the utility knife of the present invention comprises a
left side member 1A shown in FIG. 1 and a right side member 1B shown in
FIG. 3, and the left and right side members 1A and 1B are fixed together
for example by a screw 6 and a screw hole 7 shown in FIG. 6, at a state
where the structure for sliding the blade 2 in and out of the holder body
and the structure for locking and releasing the lock, such as a blade 2 of
the utility knife, a slider 3 supporting the blade 2 slidably inside the
holder body, a lock release button 4 for releasing the lock of the slider,
and the like, is stored inside the body. FIG. 2 shows the state where the
both side members are matched and fixed together.
[Blade]
The blade 2 has a plane trapezoid shape as is shown in FIG. 5, with two
cut-off portions 21 formed on the portion corresponding to the upper
portion of the trapezoid. The cut-off portion 21 is fit to a protrusion 35
mounted on the slider, constituting a temporary fixing portion 22. In the
drawing, the cut-off portion 21 close to the latter end of said blade is
fit to the protrusion 35 of the slider 3 and temporarily fixed to the
slider 3.
[Slider]
The slider 3 has a shape as is shown in FIG. 4 for example, with a front
end portion inclined to the opposite direction as the inclined portion of
the blade 2 and an opposite end portion forming a part of a square shape,
and at the position close to an end portion 3B which is opposite to the
front end portion 3A of the slider 3 and further at the upper portion of
the drawing in FIG. 5, a spring mounting hole 31 for receiving an end
portion of a spring 5 of a coil spring and the like which provides a
returning force to the slider and whose other end is held at the holder
body 1 is formed. Further, as is shown in FIG. 5, the longitudinal
direction of the upper end portion of the slider 3, that is, the position
close to said opposite end portion rather than at the center of the slider
is formed a protrusion 32 which works as an operational finger grip. This
protrusion 32 protrudes outwardly from the holder body 1 through a long
groove 11 formed on the utility knife holder body 1.
As is clear from FIGS. 8 and 9 which is a partial enlarged view of FIG. 7
showing the protruded state of the blade from the holder body, a leaf
spring member is mounted at the front portion of the slider in the drawing
whose free end is formed so as to separate farther away from the back
surface of the slider than any other member toward the back portion,
constituting a stopper 33 for locking purpose. At the free end of said
stopper 33, a stopper portion 34 bent toward the upper direction is formed
which prevents the return of the slider 3 to the latter direction by said
spring 5 when it is matched to the step portion 14 formed on the wall of
the right side member 1B of the utility knife body.
Further, the slider 3 is slidably stored in between an upper slide groove
10A and a lower slide groove 10B of the holder body 1, enabling the front
end of the blade 2 fixed on the slider 3 to be moved in and out of the
holder body 1.
[Lock Release Button]
As is most clearly shown in FIGS. 8 and 9, the right side portion 1B of the
utility knife body is provided with a hole 12 allowing the slide movement
of the lock release button 2 to be operated therethrough, and said hole 12
is formed to have a mortar shape at the portion close to the surface of
said holder, that is, a shape with a gradually enlarged diameter toward
the outside.
A step portion 13 for fitting the collar 44 formed on the head portion of
the lock release button is formed on the wall of said hole 12, and the
wall of said step portion 13 is opened directly to the interior of said
holder body 1, and the edge of said opening becomes a step portion 14 for
holding the stopper portion 34 of said slider 3.
The lock release button 4 comprises ahead portion 41 formed in a
cylindrical shape, and an elastic stripe member 42 extending from said
head portion 41. The lock release button 4 is fixed to said right side
member 1B of the body by an appropriate fixing means 43 of a screw and the
like at the end of the stripe member 42 in the position opposite the head
portion 41. The upper surface of the head portion 41 of the lock release
button 4 is formed to be positioned on the same surface as the body
surface of the knife holder in order to prevent accidental operation.
[Operation]
Next, the operation of the utility knife of the present invention will be
explained.
[When using the knife]
When using the utility knife, the user puts his/her finger on the
protrusion 32 protruding from the sliding groove 11 of the utility knife
holder body 1, and pushes it towards the direction shown by arrow a in
FIG. 4 or the front portion of the knife resisting against the spring
force of the coil spring 5. By this movement, the slider 3 slides toward
the front portion of the knife along the sliding groove 10A and 10B, and
the blade 2 fixed onto the slider 3 by a temporarily fixing portion 22
will move toward the front portion as well.
When the slider 3 slides inside the holder body 1 of the utility knife, the
stopper 33 in the shape of a leaf-spring fixed to the slider 3 will also
slide in a bent state with its front end portion (stopper portion) 34
pressing against the inner wall surface of said right side member 1B. And
when the slider 3 reaches the position corresponding to the protrusion end
of the blade 2, that is, the position of the hole 12, said contacting end
portion 34 of said stopper 33, being released of its elastic force, will
be inserted to the hole 12 formed on the inner wall surface of said right
side member 1B, and presses against the back surface of the head portion
41 of the lock release button. By this movement, the lock release button 4
will be pressed toward the side direction of the knife holder (the lower
direction of FIG. 7), but since the collar 44 of the head portion 41 of
said lock release button 4 is matched to the step portion 13 of the hole
12, any further movement of the contact end portion 34 of said stopper 33
will be prevented.
When the user releases his/her finger from said protrusion 32 at this
state, the stopper portion 34 formed on the free end of the stopper 33
will fit to the step portion 14 of the hole 12 formed on the inner wall
surface of the right side member 1B thereby preventing the return movement
of the slider 3 by the spring 5, and the blade will be locked at that
position.
By the operation described above, the user could use the knife with the
blade 2 of the utility knife being at the position protruding from the
holder body 1 without being concerned about the blade returning into the
knife.
[After using the knife]
Next, the operation for storing the blade of the knife into the utility
knife holder body after using the knife is explained.
The user presses the head portion 41 of the lock release button 4 from the
side of the knife holder body. Then, the stripe member 42 in the shape of
a leaf-spring state extending from the head portion 41 of the lock release
button 4 and the stopper 33 in the shape of a leaf-spring state of the
slider 3 connected to the head portion 41 will bend, and the stopper
portion 34 of the stopper 33 will be pushed out from the inner wall step
portion 11 of the right side member 1B. When this happens, nothing will
prevent the slider 3 from returning into the holder, so the slider 3, by
the spring force of the spring 5, will be pulled back toward the back
portion of the knife holder as is shown by arrow b of FIG. 9, and along
with the slider, the blade 2 will also be stored again inside the utility
knife body.
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